A153220 - OEIS

A153220

Self-locating strings within Pi: numbers n such that the string n is at position n (counting 3 and the decimal point) in decimal digits of Pi.

%I #7 Feb 18 2020 09:39:24

%S 4,315,360,384,47696,496498,1577526

%N Self-locating strings within Pi: numbers n such that the string n is at position n (counting 3 and the decimal point) in decimal digits of Pi.

%C a(8) > 10^9. - _Vaclav Kotesovec_, Feb 18 2020

%e a(1)=4 because the 4th character (including the decimal point) in 3.14159... is also a 4.

%t dpi = RealDigits[Pi, 10, 10000010][[1]]; Select[Range[2, 10000000], FromDigits[Take[dpi, {# - 1, # - 2 + IntegerLength[#]}]] == # &] (* _Vaclav Kotesovec_, Feb 18 2020 *)

%Y Cf. A057679, A057680, A109513, A109514

%K base,more,nonn

%O 1,1

%A _Gil Broussard_, Dec 21 2008

%E a(7) from _Vaclav Kotesovec_, Feb 18 2020